Description / Typical Applications

SNV027EC is a measurement device used in smart combiner boxes for string monitoring at photovoltaic parks.

Due to its shape, the board can be directly mounted to DIN rail fuse holders, thus minimizing the need of extra cabling on the smart combiner box assembly. The current collector bar is pre-mounted and designed for direct connection to the dissconnector switch for a more clear and cost-efficient installation.

Current measurement is performed on the positive voltage side utilising low thermal drift, high quality shunt resistors. The measurements are performed and processed by a 32-bit, high speed microcontroller. Sampling rate per channel is 667Hz. An isolated serial RS485 bus transceiver using Modbus protocol is accommodated.

The device performs several functions and measurements, among those, it calculates the average voltage, current and current square value. The averaging period is indicated-marked by a master controller broadcast command. Averaged values of different cards are synchronized and then collected. Bandwidth consumption on the bus is limited, giving the ability for a prompt response on the rest requests.

A contact input is implemented in order to monitor other components, such as the condition of an SPD. Board temperature is also measured and available through Modbus.